Cutting and gouging torch using electric arc and gas stream



Dec. 6, 1955 D. STEPATH CUTTING AND GOUGING TORCH USING ELECTRIC ARC AND GAS STREAM r iled June 15,

JNVENTOR. Myeo/v 0. 575% TH BY 63 x44, M 46AM A r TOE/VF V5 United States Patent CUTTING AND GQUGHNG TURCH USHNG ELECTRHC ARC AND GAS STREAM Myron D. Stepath, Bremerton, Wash, assignor to Areair This invention relates to improvements in electric arc torches utilizing a gas stream directed continuously upon or over the heated area of the work, whether for welding or for cutting and gouging purposes. The invention is herein illustratively described by reference to its presently preferred form as applied to an electric are cutting and gouging torch, but it should be understood that certain variations and modifications therein may be made without departing from the essential features involved.

Since the equipment used in a foundry or like establishment ordinarily receives rough treatment, it is desirable to protectively encase working parts which could easily be damaged. It is also desirable in such applications to minimize the number of controls requiring the operators attention. In the case of a welding torch or a cutting and gouging torch, the operator is usually handicapped by dark goggles and heavy gloves, hence any simplification in the means for controlling the equipment is advantageous. Moreover, because the jobs often to be done with such torches are time-consuming and tedious, anything which can be done to lessen the physical strain on the operator, such as reducing the weight of a torch, improving the ease of handling and control thereof and promoting better visibility of the work area, is especially desirable.

With these and other considerations in view, certain objects of the present invention comprise the provision of an improved cutting and gouging torch which is simple in construction, relatively inexpensive, rugged, durable, compact, light in weight and employs control elements, such as a gas valve control, which are entirely enclosed so as to eliminate the usual projecting valve handle or like encumbrances subject to damage and tending to get in the operators way.

A related object of the invention is an improved cutting and gouging torch or the like which is relatively easy to use and involves a minimum of control requirements. A more specific object is an automatic control for the gas valve in such a torch causing the flow of gas to be initiated automatically when an electrode is inserted in the torch, and to be terminated automatically when the electrode is removed therefrom. Thus the invention provides a means by which the operator is relieved of the usual hand-cramping task of holding an air valve control in constant depressed position during use of the torch, or of operating a detent held valve; moreover, the operator is assured of the fact that the pressure of the stream of gas directed on the work remains as constant as the pressure of the source of gas.

An important feature of the invention resides in a cutting and gouging torch comprising electrode holder means having an opening or socket therein to receive an electrode rod, gas jet orifice means associated with the electrode holder and supplied with gas under pressure through conduit means internal to the torch, normally closed valve means cooperating with such conduit means, and valve-actuating means having a control element normally projecting into the electrode holder socket in the 2,726,309 Fatented Dec. 6, 1955 Ice closed position of the valve, but displaced from this position to open the valve when an electrode is inserted into the holder and presses the control element out of the holder socket. The electrode-contacting control element for the automatic valve-actuating means serves the additional purpose of pressing the electrode against the side of the holder socket to improve its electrical contact therewith and also to prevent it from dropping out of the socket accidentally in the event that the electrode rod fits loosely in the holder. In the preferred form of the invention, this valve control element comprises the tip or end portion of an elongated valve rod which rod is normally held in valve-closed position by the force of a valve spring and/or the pressure of gas in the torch. When the rod is displaced longitudinally by insertion of an electrode in the holder, these same forces press the tip of the rod against the side of an electrode as a means of holding the electrode more securely in place and of establishing improved electrical contact thereof with the holder Wall.

These and other features, objects and advantages of the invention will become more fully evident from the following description thereof by reference to the accompanying drawings.

Figure 1 is a longitudinal sectional view of the improved cutting and gouging torch with a rod electrode held therein.

Figure 2 is a perspective view of the electrode holder portion of the torch.

Figure 3 is a longitudinal sectional view taken on line 33 in Figure l and illustrating certain details of the gas conduit arrangement in the torch.

The torch body comprises an elongated tubular member 10 of steel or other suitable metal, the base end of which retains a fitting 112. The end of a flexible gas supply hose 14 connected to a suitable source of gas under pressure is clamped around the end of this fitting by a retaining band 16. The gas hose also serves as an insulating shield for the flexible electric conductor 18 received coaxially therein, the external diameter of the electrical conductor being materially less than the internal diameter of the hose to provide a passage for the movement of gas through the hose. The end of this conductor is welded, brazed or otherwise permanently secured in a socket provided in the tip of the fitting 12 so that the fitting electrically interconnects the conductor 18 and the tubular torch body 10. Gas under pressure in the hose 14 flows into the interior of the member it: through the ends of a transverse bore 12a and an intersecting longitudinal bore 12b in this fitting.

The opposite end of the body member it is internally threaded to receive the threaded base of the electrode holder 20. This holder has an electrode socket or bore 22 therein open at both ends and inclined to the axis of the body member in by a desired angle for convenience in using the torch. The torch handle comprises an insulating tube 24 surrounding the coaxial hose connections and the base portion of the body member 16, being spaced outwardly from the member iii by insulating rings 26 and 28 spaced apart along the length of the latter. A set screw 30 with insulating tip is threaded through the handle 24 and ring 28 for holding the handle in place lengthwise of the member 10. A concave-convex metal shield surrounding the torch body is interposed as a handguard between the handle 24 and the electrode holder 2%. The shield 32 has a' tubular extension 34 surrounding the body member lib between the handle and the electrode holder. The shield members 32 and 34 are mounted on the insulating rings 26 and 36 secured on the body member 10 and are thereby maintained out of electrical contact with such body member. An insulating tape 38 is wound around the body memberlll within the shield member 34 in order to eliminate the possibility of arcing due to ground contacts of either shield member, 32 or 34. The ring 36 has a flange gripped between the complementally threaded ends of the body member it and the electrode holder 20. Thus the tubular torch body 1% is surrounded over substantially its entire length by insulating means.

Two gas jet orifices 40 are formed in that face of the electrode holder from which the working end of an electrode E projects during use of the torch. These orifices, formed by bores in the end of the holder parallel to the electrode socket 22, are directed substantially parallel to the axis of a socketed electrode from locations immediately adjacent opposite sides thereof so that the streams of gas issuing therefrom are concentrated on the heated area of the work. For purposes of the present invention, however, the specific nature or number of the gas jet orifices are immaterial.

In order to conduct gas under pressure from the interior f the tubular member to the orifices 48 the threaded base of the electrode holder 29 has a pair of inclined bores 42 which extend from a relatively large axial bore 44 in the holder base at locations inside the rim of the bore 4-4 and intersect the respective bores forming the two orifices 40. The rim of bore 4-4 is chamfered and serves as a gas valve seat. The diameter of bore 44 is reduced somewhat near its end which ente s the electrode holder socket bore 22 and serves as a guide for the sliding valve rod to be described.

An elongated valve rod 46 is received for longitudinal reciprocation inside the tubular torch body member 10. The base of this rod has an enlargement 46a slidably engaged with the inside wall of member 10 and flattened at one or more places around its periphery or otherwise formed to permit free flow of gas past this enlargement. A loaded helical compression spring 48 received between the rod base and the fitting 12 urges the valve rod in the direction toward the electrode holder. The combined force of this spring and the pressure of gas entering the interior of the member 10 normally hold the annular valve 50, formed as a shoulder on such rod, tightly against its seat on the rim of the bore 44, representing the closed position of the valve. Beyond the valve 50, the rod 46 extends to a tip portion 4612 which constitutes a valve control plunger slidably engaged in the reduced portion of the bore 44. The main portion of the bore 44 is somewhat larger in diameter than this tip portion 46b so that gas under pressure flowing past the valve 50 may flow freely into the entrances of the inclined bores 42. In the valve-closed position of the rod 46 the end of its control plunger 46b projects a short distance into the socket bore 22 of the electrode holder 20 as shown by dotted lines in Figure l.

The diameter of the electrode holder bore 22 is chosen preferably just slightly larger than that of an electrode E to be used in the torch, so that the electrode rod may be freely slid into and out of this socket bore. Normally the electrode rod is slid into operating position point first in the direction of the arrow (Figure 1) and in so doing will contact the end of the valve rod tip portion 46b and wedge its way past such tip portion so as to displace the valve rod in the direction to open the valve. The tip portion of the electrode E is shown in broken lines in Figure 1 as it just contacts the tip portion 4612. Thus by the act of inserting an electrode in the holder 20 the gas valve 50 is automatically unseated to permit free flow of gas under pressure from the hose 14, through the interior of the torch body 10 and past the valve 50 for outflow through the jet orifices 40. This two-fold operating condition of the torch, namely positioning of the electrode and initiation of gas flow is thus accomplished in a single relatively simple operation.

When the electrode is removed from the holder, the gas is turned off automatically thereby, due to the combined forces of spring 48-and gas pressure acting on the valve rod. In the valve-open position of the rod 46, with an electrode E inserted in the holder, these same spring and gas pressure forces press the end of the valve control plunger 46]; firmly against the side of the electrode, hence serve to prevent the latter from dropping out of the torch accidentally. Moreover, such pressure on the electrode improves its electrical contact with the holder, which is desirable in a high-current device of this nature. Also the added weight and cost of a manual valve control means ordinarily provided in such torches are eliminated by the present invention.

Another advantage of the illustrated form of this invention is the fact that the annular shoulder valve 50 itself formed on the valve rod 46 serves as a stop limiting penetration of the tip of the valve rod into the bore 22 at a position such that the electrode is easily wedged past such tip while being inserted in the holder 20.

These and other conveniences and advantages of the invention will appear to those skilled in the art.

I claim as my invention:

1. An electric arc torch comprising a torch body, electrode holder means on said torch body having a socket opening therein for removable insertion of an electrode into said holder means, gas jet orifice means physically associated with said holder means in predetermined directional relationship with said socket opening, gas conduit means extending through said torch body and leading to said orifice means, normally closed valve means cooperating with said conduit means for opening and closing said conduit means to the flow of gas therethrough, said valve means being mounted internally of said torch body, and valve actuating means including a control element normally projecting into the space in said holder means socket opening occupied by an electrode inserted in said holder means, said control element being yieldably mounted to permit displacement of said control element out of said space by contact thereof with an electrode inserted into said opening, said control element being connected to said valve means for opening the same automatically by such control element displacement, and means operatively connected to said control element and valve means yieldably urging the same toward their respective normal positions.

2. An electric arc torch comprising a torch body, electrode holder means on said torch body having a socket opening therein for removable insertion of an electrode into said holder means, gas jet orifice means physically associated with said holder means in predetermined directional relationship with said socket opening, gas conduit means extending at least partly through said torch body and leading to said orifice means, normally closed valve means cooperating with said conduit means for opening and closing said conduit means to the flow of gas therethrough, and valve actuating means including a control element normally projecting into the space occupied by an electrode inserted in said holder means, said control element being yieldably mounted to permit displacement of said control element out of said space by contact thereof with an electrode inserted into said opening, said control element being connected to said trode socket bore therein extending generally transversely to said passage, said electrode holder means having an opening therein generally aligned with said passage, an elongated valve rod slidably received for longitudinal reciprocation in said passage, valve actuating means on said valve rod extending slidably through said holder means opening and normally into the space in said holder means socket bore occupied by an electrode inserted therein, gas jet orifice means in said torch arranged to cooperate with said electrode holder means therein, gas duct means connected to said orifice means and normally closed valve means in said duct means operable to open and close such duct means, said valve rod being connected to said valve means for opening the same automatically by displacement of said valve actuating means from said bore by insertion of an electrode into said bore, and yieldable means cooperating with said valve rod normally urging the same into valve-closed position with said valve actuating means projecting into said holder means bore.

4. The torch defined in claim 3, wherein the yieldable means comprises a spring progressively stressed by displacement of the valve actuating means from the holder means bore, whereby force of said spring presses such valve actuating means against the side of an electrode in the socket bore.

5. The torch defined in claim 4, wherein the gas duct means includes the longitudinal passage in the torch body member and the valve means comprises an element car ried by the valve rod in said passage, and means in said passage forming a seat for said valve element.

6. The torch defined in claim 3, wherein the yieldable means comprises a piston in the gas duct subjected to gas pressure and continuously pressing the valve actuating means against the side of an electrode in the socket bore.

7. The torch defined in claim 3, wherein the yieldable means comprises a spring progressively stressed by displacement of the valve actuating means from the holder means bore, whereby force of said spring presses such valve actuating means against the side of an electrode in the socket bore and piston means in the gas duct subjected to gas pressure and cooperating with said spring in continuously pressing the valve actuating means against the side of such electrode.

3. The torch defined in claim 3, wherein the gas duct means includes the longitudinal passage in the torch body member and the valve means comprises an element carried by the valve rod in said passage, and means in said passage forming a seat for said valve element.

9. An electric arc torch comprising an elongated tubular torch body member, electrode holder means mounted on one end of said body member and having an electrode socket bore therein extending generally transversely to said body member, said electrode holder means having an opening therein generally aligned with the tubular passage in said body member, an elongated valve rod slidably received for longitudinal reciprocation in said passage, said valve rod having a valve actuating end portion projecting slidably through said holder means opening and normally into the space in said holder means socket bore occupied by an electrode inserted therein, gas jet orifice means in said electrode holder means, gas duct means in said holder means connected to said orifice means and communicating with said tubular passage,

means for introducing gas under pressure into said passage for ejection through said orifice means, and normally closed valve means on said valve rod constructed and arranged to control flow of gas through such duct means, said valve means being opened automatically by displacement of said valve actuating end portion from said bore by insertion of an electrode into said bore, and yieldable means cooperating with said valve rod normally urging the same into valve-closed position with said valve actuating end portion projecting into said holder means bore.

10. An electric arc torch comprising an elongated torch body portion, an electrode holder carried by said body portion and having an electrode receiving socket therein opening generally transversely to the length of said body portion, plunger means guided for longitudinal reciprocation in said body portion and having an electrode-contacting end portion normally projecting into said socket but yieldably displaceable therefrom by an electrode inserted into said bore, means yieldably urging said plunger into said normal position thereof, gas jet orifice means in said torch constructed and arranged to cooperate with said electrode, normally closed valve means in said torch controlling flow of gas to said orifice means, and means operatively connecting said plunger means to said valve means for opening the latter automatically by said displacement of said electrode-contacting end portion, said valve means being permitted to close in the normal position of said end portion.

11. The electric arc torch defined in claim 10, wherein the valve means comprises a valve element carried by the plunger means internally of the torch body portion.

12. An electric arc torch comprising an elongated torch body portion, an electrode holder carried by said body portion and having an electrode receiving socket therein,

electrode retaining means having an electrode-contacting end portion normally projecting into said socket but yieldably displaceable therefrom by an electrode inserted into said bore, means, yieldably urging said retaining means into said normal position thereof and, when so displaced, against the side of an electrode in said socket, gas jet orifice means in said torch constructed and arranged to cooperate with said electrode, normally closed valve means in said torch controlling flow of gas to said orifice means, and means operatively connecting said retaining means to said valve means for opening the latter automatically by said displacement of said electrode-contacting end portion, said valve means being permitted to close in the normal position of said retaining means.

References Cited in the file of this patent UNITED STATES PATENTS 1,534,688 Collins Apr. 21, 1925 2,443,592 Birch June 22, 1948 FOREIGN PATENTS 237,552 Great Britain Aug. 6, 1925 

